As a known facsimile apparatus connectable with a data processing terminal, such as a personal computer, there is a facsimile apparatus connected with the terminal through a two-way parallel port (compliant with IEEE 1284) interface, e.g., Centronics or the like, or a Universal Serial Bus (USB) interface, as disclosed in Japanese Patent Application Laid-Open No. 7-288625.
In an image processing system constructed with the aforementioned facsimile apparatus and data processing terminal, as a connection form between the facsimile apparatus and data processing terminal, a single logical interface is assigned to a single physical interface.
Furthermore, the main control unit and printing unit included inside the facsimile apparatus are connected through one-way parallel communication and a two-way serial interface.
As an example of the facsimile apparatus which constitutes the image processing system according to the conventional art, a brief configuration of an image processing apparatus 1100 is described in detail with reference to FIG. 12.
In the image processing apparatus 1100, a CPU 1101 serving as a system control unit controls the entire image processing apparatus 1100. ROM 1102 stores control programs and an incorporated operating system (OS) program or the like, which are executed by the CPU 1101. Each of the control programs stored in the ROM 1102 executes software controlling, e.g., scheduling, task switch and so on, under the control of the incorporated OS stored in the ROM 1102.
RAM 1103, configured with SRAM (static RAM) or the like, stores program control variables or the like and set values registered by an operator as well as control data of the image processing apparatus 1100 and so on, and includes a buffer area for various works. Image memory 1104, configured with DRAM (dynamic RAM) or the like, stores image data.
A data conversion unit 1105 performs image data conversion, such as interpretation of a page description language (PDL) or the like, CG (computer graphics) development of character data and so on.
A reading control unit 1106 performs various image processing, e.g., binarization, halftone processing or the like, on an image signal obtained by a reading unit 1107, which optically reads an original document with the use of a contact image sensor (CIS) and converts the read data to electric image data, through an image processing control unit (not shown) and outputs high-definition image data. Note that the reading control unit 1106 and reading unit 117 are adaptable to both a sheet-reading control method, which performs reading by a CIS image sensor fixed at a predetermined position while conveying an original document, and a book-reading control method, which scans an original document placed on a platen while moving the CIS image sensor.
An operation display unit 1108, including numeric value input keys, character input keys, one-touch telephone number keys, mode setting keys, an OK key, a cancel key and so on, is constructed with an operation unit for a user to decide image transmission destination data or to perform registration operation of setting data, various keys, a light-emitting diode (LED), a liquid crystal display (LCD), and a display unit for displaying operator's various input operations and an operation state or status of the image processing apparatus 1100.
A communication control unit 1109 is constructed with a modulator-demodulator (MODEM), a network control unit (NCU) and so on. The communication control unit 1109 is connected with an analogue communication line (PSTN) 1131 to perform, for instance, communication control according to the T30 protocol, or perform line control such as call out and call in of the communication line.
A resolution conversion processing unit 1110 performs resolution conversion control, such as millimeter-to-inch resolution conversion of image data. Note that in the resolution conversion processing unit 1110, enlargement/reduction processing of image data is possible. A coding/decoding processing unit 1111 performs coding/decoding processing on image data (non-compressed or compressed in accordance with MH, MR, MMR, JBIG, JPEG or the like) handled by the image processing apparatus 1100, or performs enlargement/reduction processing.
A print control unit 1112 performs various image processing, e.g., smoothing, print density correction, color correction and so on, on image data subjected to printing through an image processing control unit (not shown), and converts the data to high-definition image data to be outputted to an IEEE 1234 host control unit 1114 (to be described later).
A USB function control unit 1113, which performs communication control of a USB interface, performs protocol control according to the USB communication standard, converts data transmitted from a USB control task executed by the CPU 1101 into a packet, and transmits the USB packet to an external data processing terminal, and inversely, converts a USB packet from an external data processing terminal into data and transmits the data to the CPU 1101.
The IEEE 1284 host control unit 1114 is a control unit for performing communication according to a protocol designated by a compatibility mode of the IEEE 1284 communication standard. The compatibility mode of the IEEE 1284 communication standard, capable of one-way data communication, can connect one host (master) with one peripheral (slave). The IEEE 1284 host control unit 1114 serves as the host in the IEEE 1284 communication, and transmits only print data to a printing unit 1115 (to be described later).
The printing unit 1115, which is a printing device configured with a laser beam printer, inkjet printer or the like, prints color image data or monochrome image data on a printing material. The printing unit 1115 communicates with the IEEE 1284 host control unit 1114 according to a protocol designated by the compatibility mode of the IEEE 1284 communication standard. Particularly the printing unit 1115 serves as the peripheral. In the IEEE 1284 communication, the printing unit 1115 receives print data from the IEEE 1284 host control unit 1114. Meanwhile, the printing unit 1115 performs asynchronous serial interface (UART) communication with a serial I/F control unit 1116 (to be described later). In the asynchronous serial interface communication, the printing unit 1115 receives a command from or transmits print status data to the serial I/F control unit 1116.
The serial I/F control unit 1116 is a control unit for performing asynchronous serial interface communication. Asynchronous serial interface communication is low-speed data communication capable of full-duplex transmission. The serial I/F control unit 1116 transmits a command to or receives print status data from the printing unit 1115.
The aforementioned components 1101 to 1106, 1108 to 1114 and 1116 are connected to each other through a CPU bus 1121 controlled by the CPU 1101.
In an image processing system having the above-described conventional image processing apparatus, a single logical interface is assigned to a single physical interface as mentioned above. Furthermore, in addition to a one-way physical interface for the main control unit to transmit image data to the printing unit for printing, another two-way physical interface is necessary for acquiring status information of the printing unit. This causes problems of an increased product designing work and complicated control.
In order to solve the above problems, a universal serial bus (USB) is adopted to the physical interface between the data processing terminal and facsimile apparatus, and also to the physical interface between the control unit and printing unit of the facsimile apparatus, thereby providing a plurality of logical channels compliant with the USB standard (USB composite device). By virtue of this configuration, it is no longer necessary to provide a physical interface for acquiring status information of the printing unit in addition to the interface provided for the main control unit to transmit image data to the printing unit. As a result, a reduced number of designing processes, ease of making changes, and improved data permeability can be expected.
Moreover, generally in a case where an external data processing terminal uses a printer to print out image data, it is necessary to start driver software on the external data processing terminal and acquire status information of the printer through the USB. At the time of USB connection, a printing unit information registration command is transmitted from a USB host via an end point 1 (Bulk-Out), serving as a USB logical channel, to register in the printer items of the printing unit status information to be acquired. At desired timing of status information acquisition, a reverse request (In-Token) is transmitted from the USB host using an end point 2 (Bulk-In), serving as a USB logical channel. In response, information regarding the items registered in initial setting is returned from a USB function unit of the printer using the end point 2.
Similarly to the foregoing method, in a case where the aforementioned external data processing terminal is connected to the facsimile apparatus via the USB in the above-described image processing system to print out image data, a printing unit information registration command transmitted from driver software, which is launched on the data processing terminal, is received by the control unit of the facsimile apparatus, and the command is transferred to the printing unit via the end point 1 of the internal USB host, thereby registering in the printing unit items of the printing unit status information to be acquired by the driver software. At desired timing of acquisition, the control unit of the facsimile apparatus transmits a reverse request from the USB host using an end point 2. In response, information regarding the registered items is returned from the USB function unit of the printing unit using the end point 2, thereby providing information of the printing unit necessary to the driver software working on the data processing terminal. In the above method, since the printer driver software installed in the printing unit can be used without alteration, it provides an advantage in that controlling of the printing unit can also be realized with ease.
Furthermore, in order to perform operation of the functions, such as copying, recording of facsimile reception or the like, it is necessary for the control unit of the facsimile apparatus to regularly monitor the status of the printing unit through the USB. Therefore, as similar to the above-described method, the following control can easily be considered. More specifically, at the time of turning on the power, the control unit of the facsimile apparatus transmits a printing unit information registration command from the USB host using the end point 1 to register items of the printing unit status information. At desired timing of acquisition, the control unit of the facsimile apparatus transmits a reverse request from the USB host using the end point 2. In response, information regarding the registered items is returned from the USB function unit of the printing unit using the end point 2. According to the above method, there is an advantage in that the acquisition control of printing unit status information becomes common.
In the image processing system having the above-described configuration, when the power is turned on, items of the printing unit status information are registered in the printing unit for internally monitoring the facsimile apparatus. However, if a data processing terminal is connected with the facsimile apparatus and printing unit status information is registered from the driver software, the registration is written over the items which have been registered in the printing unit for internally monitoring the facsimile apparatus. Because the driver software working on the data processing terminal and the main control unit of the facsimile apparatus request printing unit status information via the same logical channel using the same method, it is unable to distinguish whether a reverse request from the printing unit is from the main control unit or from the external data processing terminal. Therefore, in response to a reverse request from the main control unit, status information for the items registered by the driver software is returned. In a case where items requested and registered by the driver software are different from items requested and registered for internally monitoring the facsimile apparatus, the printing unit status information returned in response to the reverse request becomes inconsistent.
Furthermore, if the driver software working on the data processing terminal and the internal unit of the facsimile apparatus attempt to acquire printing unit status information via the same channel (end point 1 or 2), the control unit must determine from where the status information is transferred, in order to correctly return a response. Therefore, it may cause disadvantages, such as complicated control or delayed response timing.
In addition, since the end point 1 of the USB is normally used as an image data transmission channel, it tends to be busy due to printing unit errors. Such errors cause interruption in transmission of the printing unit information registration command using the end point 1,thus disabling the registration of the printing unit status information.